Dairy Glossary

It is said that the dairy cow (or maybe the dairy goat) is the mother of mankind. In today's modern dairy agri-business venture the dairy cow is a virtual "cash-cow". Listed below are the most commonly used terms and phrases associated with the dairy industry along with some general animal husbandry terms.

A   B   C    D   E   F    G    H    I    J    K    L   M   N   O   P    Q    R    S   T    U    V   W   X   Y   Z

A                                                            Return To Index

Premature expulsion of the fetus from the uterus.

Age and Month-of-Calving Factors
Factors used to eliminate the environmental effects of different ages and months of the year at calving. These factors standardize lactation records for genetic evaluations.

Age at Last Calving
Age determined by subtracting the cow's birth date from her most recent calving date.

Agricultural Research Service (ARS)
The research branch of the U.S. Department of Agriculture.

Animal Improvement Programs Laboratory (AIPL)
A U.S. Department of Agriculture research service computing laboratory that calculates genetic evaluations of cows and sires using data collected through the DHI system.

Abbreviations commonly used to describe alternate morning(evening monthly types of testing plans. Milk weights and samples are collected at the morning milking for 1 month and at the evening milking the following month. Accurate milking times for all milkings are necessary to correctly calculate herd records. AP programs are available for official and un- official testing plans; however, approved monitoring devices to record milking times are required for official records.

Approved Meters and Weighing and Sampling Devices
Mechanical or mechanical-electronic devices that record milk weights when milking with a pipeline milking system. The device must obtain accurately a representative sample for milk component testing. These devices may be portable or fixed in place on the farm and must meet accuracy levels as indicated in Appendix to Official DHI Rules #1 a, b and c.



B                                                             Return To Index

Babcock Test
Traditional method of measuring the butterfat content of milk, which may be used for calibrating modem electronic testing devices.

Balanced Ration
A ration containing all the dietary requirements to meet the purpose for which it is being fed.

The prelisted sheet used in the DHI system for collection and input of DHI data and information at the farm.

A simplified, inexpensive testing plan to provide basic management information to dairy farmers. Since basic plans involve owner sampling and recording, Official DHI Rules need not be followed.

Bovine Growth Hormone (See Somatotropin.)

Breeding Value
The genetic merit of an animal for a certain trait. (May also be expressed as twice the animal's transmitting ability.)

A noncorrosive milk preservative in tablet or granular form (2-Bromo-2-Nitro propane-1,3 diol).



C                                                            Return To Index

California Mastitis Test (CMT)
A mastitis screening test useful for determining the somatic cell content in milk. A reagent is required to react with nuclear material of cells present in milk to form a gel. (This is a cowside test and requires a subjective score based on the amount of gel formed when the milk is mixed with the reagent.)

One of a group of several phosphoproteins that comprise the principal proteins in milk.

A conformation appraisal program offered by a breed association to evaluate each animal's resemblance to the breed's ideal. A numerical score is assigned each animal.

Component Sampling (CS)
Milk samples collected for component testing. The DHI testing plan (APCS) indicates milk samples are collected in the morning for 1 month and in the evening the following month. Milk weights are collected at all milkings in the APCS testing plans and APCS programs are available for official and unofficial testing plans.

Composite Herd Average
In large herds, or herds with multiple units of cows, composite herd averages are calculated for the total (or composite) of the individual units.

Feeds low in fiber and high in total digestible nutrients and energy.

Fertilization of the ovum.

Conception Rate
Total number of conceptions obtained divided by total number of services.

Confidence Range (CR)
Indicates the accuracy in the estimation of a sire's genetic merit in a sire proof by giving a probable range for future summaries.

Cows of the same breed that were born and raised, and initiated their lactations during similar periods. Usually separated into two lactation groups for comparison--first lactation and all other lactations.

Contemporary Comparison
Method for estimating the transmitting ability of bulls and cows using information on contemporaries.

Cooperative Extension Service (CES)
The state, university and county educational outreach service of each state land-grant institution. This service extends the research results and educational programs of land-grant institutions to all the people in the state. CES is a cooperating member serving the educational function of National Cooperative Dairy Herd Improvement Program (NCDHIP).

Cow Index (CI)
A measure of a cow's genetic merit for a given trait by estimating her transmitting ability.

The removal of cows from a herd as a result of low production or other factors that reduce the profitability of the cow.



D                                                             Return To Index

Dairy Herd Improvement (DHI)
DRPC Code 00. Official DHI type of testing plan that requires supervision and compliance with all Official DHI Rules (DHI abbreviation is used commonly to designate the testing plans).

DHI Records
Generic term used to classify any records computed by the Dairy Record Processing Centers.

DHI Supervisor
An officially trained and DHIA-certified employee qualified to collect milk samples and record milk weights for all official types of testing plans.

Dairy Herd Improvement Association (DHIA)
The title given to local, regional, state or national dairy collecting and recordkeeping cooperatives and organizations.

Dairy Herd Improvement Registry (DHIR)
DRPC Code 20. Abbreviation used to designate Official DHIR type of testing plan for registered cows. Record supervision and verification are required in compliance with Official DHI and DHIR Rules.

Dairy Records Processing Center (DRPC)
A computing facility where information from the periodic tests in NCDHIP herds is summarized and analyzed and where information to be used in future management decisions is prepared for the dairy producer.

Dairy Cattle Breed
Group of dairy cattle having a common origin and identifiable traits (frequently color). The major U.S. breeds are Ayrshire, Brown Swiss, Guernsey, Holstein, Jersey and Milking Shorthorn.

Dairy Cow
A bovine from which milk production is intended for use or sale for human consumption, or is kept for raising replacement dairy heifers.

Dairy Goat Breed
Group of dairy goats having a common origin and identifiable traits (frequently color). The major U.S. breeds are Alpine, LaMancha, Nubian, Oberhasli, Saanen and Toggenberg.

Dairy Goat
Any goat from which milk production is intended for use or sale for human consumption, or is kept for raising replacement dairy kids.

The female parent of any dairy animal.

Daughter-Herdmate Comparison
Amount by which a daughter of a bull differs in yield or other traits from the average of cows of other bulls' daughters of the same breed in the same herd during the same period.

Days in Milk
The number of days during the present lactation that the cow has been milking, beginning with the last date of calving to the current test date.

Direct Microscopic Somatic Cell Count (DMSCC)
Microscopic count of the actual number of somatic cells in milk. (This system is used to check and verify electronic cell count machines used in DHI laboratories.)

Disallowed Practices
Certain procedures or practices that may impair or attempt to impair the reliability of any Official DHI record.

Donor Dams
Genetically superior cows from which embryos are collected and transferred to recipients to allow these cows to produce a greater number of offspring than possible in a normal reproduction scheme.

Dry Cow
Any cow that has calved once and is not producing milk.

Dry Date
First calendar day the cow is not milked (See Dry Period).

Dry Period
Period of nonlactation following a period of lactation. This nonlactating time is generally a 5 to 8-week rest period before freshening.



E                                                             Return To Index

A tag that generally is attached to the ear of a dairy cow for easy and accurate identification.

Embryo Recipient
Any cow or heifer that serves as a surrogate mother and carries the embryo of another cow throughout the development of the embryo and birth of the calf.

Embryo Transfer
Modern technology that allows dairy cows to be superovulated and bred. The fertilized eggs (ova) are flushed from the donor's uterus, and transferred to a recipient that serves as a surrogate mother. The fertilized ova may be frozen and stored indefinitely before they are thawed and transferred to recipients. DHI programs and rules assist dairy farmers in using this new technology.

Estimated Producing Ability (EPA)
An estimation of the amount of milk and/or components that a cow will yield above or below herdmates based on the cow's pedigree information and performance, if available. (Also called Estimated Relative Producing Ability or ERPA.)

Estimated Transmitting Ability (ETA)
An estimation of an animal's genetic transmitting ability based on pedigree information and the animal's performance, if available. (Also called Estimated Average Transmitting Ability or EATA.)

Pertaining to the entire cycle of reproductive changes in the nonpregnant female animal.

Period of sexual receptivity in females. Also referred to as a heat period in dairy cattle.

Extension Dairy Scientist
Also referred to as Extension dairy specialist. A land-grant university or college dairy scientist with responsibilities for educational outreach programs. May be designated "for NCDHIP if given specific DHI program responsibilities.



F                                                             Return To Index

Fat  (See Milk Fat.)

Filter DNA
A mastitis screening test useful in determining somatic cells present in milk by filtering and measuring the amount of deoxyribonucleic acid (DNA) produced.

A crop that is high in fiber and grown especially to feed ruminant animals.

Fraudulent Practices
Any practice a herd owner or his or her agent may use that impairs or attempts to impair the reliability of any official DHI record.

A sterile heifer born twin with a bull.

Freeze Branding
A method of identification to aid in easily identifying dairy cattle. Most commonly, liquid nitrogen is used to lower the temperature of a branding iron to permanently lighten the hair color where applied.

To give birth to a calf and simultaneously to begin a period of lactation. Also referred to as parturition.



G                                                             Return To Index

Generation Interval
The average age of parents when their offspring are born.

Genetic Appraisal
Cows and sires are evaluated by researchers at the Animal Improvement Programs Laboratory, ARS-USDA, to determine their genetic values. Cows are appraised according to milk and component transmitting abilities and assigned cow indexes. Sires are appraised and assigned predicted differences for milk and components.

Genetic Base
The average genetic merit of a population (usually a breed) at a specified period, which is used as a reference point to express a genetic difference from a base population (genetic merit of cows and bulls).

Genetic Merit
The genetic value of the animal used in a breeding program. (Also see Breeding Value.)

Genetic Trend
Genetic change per year for a trait in the population.

The period of fetal development between fertilization of the ovum and birth of the offspring.

Grade Cattle
An animal possessing the distinct characteristic of a particular breed but not registered with a breed association.



H                                                             Return To Index

A female dairy animal that has yet to give birth to a calf.

Herd Average
Average milk and component production per cow for all cows in the herd unit for 12 months. Herd averages that are calculated include rolling herd average, lactation average and ME lactation average.

Herd Code
An exclusive reference number that identifies every DHI herd. The first two numbers identify the state, the next two the county or association and the final numerical series identifies the herd within a county.

Herd Owner
The declared owner of a herd of dairy cattle as recorded on a legal document, registration papers or other official documents.

Herdmate Comparison
Method of estimating genetic transmitting ability in which a cow's yield is compared to that of other cows in the same breed from different sires that calved in the same herd during the same season.

The fraction of variation in a trait that is genetically transmissible from parent to offspring.



I                                                             Return To Index

Incomplete Record
A cow's production in a lactation that is terminated early for some reason. (May be referred to as a record in progress.)

Induced Lactation
A lactation that is artificially initiated by the use of hormones.



L                                                             Return To Index

Lactation Average
Sometimes referred to as DHIR Lactation Average. Actual 305-day average milk and component production for all cows in the herd that was completed during a 12-month period. It may or may not be a calendar year. (Since dry days are not included, lactation averages usually are 8 to 15 percent higher than rolling herd averages.)

Lactation Record
The total milk and components produced by a cow beginning on the day of calving and ending on the day the cow goes dry. For purposes of genetic comparison, 10-month (305-day) lactation records are the standard of the industry. A 306 to 365-day lactation record may be used for promotion. Lactation records greater than 365 days will not be published.

Lactation Totals to Date
The production totals for milk and components through the current test date.

Lactose  (See Milk Lactose.)

Lifetime Production Totals
The production totals for milk and components for a cow since her first calving (or first time on DHI test). Totals will include production beyond 365 days in a lactation, production credits for an abnormally initiated record and any production from prepartum milking.

Linear Score (SCC)
Linear scores for somatic cell counts (SCC's) convert SCC logarithmically from cells per milliliter to a linear score from 0 to 9. The linear score has a straight line, inverse relationship with milk yield. An increase of one in the linear score is associated with a 400-pound decrease in lactation milk yield or a 1.5-pound drop in daily yield.

Long Test Interval
Routinely, tests are conducted each 15 to 45 days, or approximately one each month. An emergency or supervisor vacation schedules may extend the interval beyond 45 days. For herds on official plans, reasons for a long test interval (48 to 75 days) must be reported on the barnsheet by the supervisor. Official status of the record is lost if the interval exceeds 75 days.



M                                                             Return To Index

Mature Equivalent (ME)
Standardization of lactation records to the level of yield that would have been attained by each cow if she had been a mature cow and calved in the month of highest calving frequency for her breed.

Mature Equivalent (ME) Lactation Average
ME average milk and component production per cow for all cows in the herd for the previous 365 days. ME lactation averages are updated with each new test. Since ME represents an estimate of mature production, an ME lactation average usually is 5 to 10 percent higher than the rolling herd average.

Inflammation of the mammary gland.

Memorandum of Understanding
The formal agreement between National DHIA, Inc., the Cooperative Extension in each state, ARS-USDA, ES-USDA and the Extension Committee on Organization and Policy (ECOP) for cooperatively carrying out the programs and policies of the National Cooperative Dairy Herd Improvement Program.

A small and powerful, yet inexpensive, computer that can be used on the farm to keep financial, herd management and other types of records. Microcomputers also can communicate with other computers.

Milk Composition
Average composition of dairy cow milk includes the following constituents: 87 percent water, 3.5 percent protein (casein), 5 percent sugar (lactose), 3.7 percent fat and 0.8 percent minerals and vitamins.

Milk Fat
A complex mixture of triglycerides containing numerous fatty acids. Milk fat is one of the components of milk, which provides the basis for differential pricing of milk. DHI laboratories use electronic photometry and infrared absorption for rapid milkfat tests. Milk fat also is referred to as butterfat or fat.

Milk Lactose
Average milk contains just under 5 percent lactose. Lactose is the sugar in milk. It is converted to lactic acid in sour milk and is used in the production of various cheeses and buttermilk. Little variation in lactose content exists among cows or breeds.

Milk Only (MO) Record
Type of testing plan where only milk weights are recorded and no milk samples are collected for component sampling. This plan is intended for management use only. The records made are not official and DHI Rules need not be followed.

Milk Preservative
A compound used to stabilize and to prevent decomposition of milk samples sent to DHI laboratories for component analysis.

Milk Protein
A complex chemical substance contained in milk, which upon hydrolysis breaks down to amino acids. Milk proteins are an excellent source of the necessary amino acids and are economically important because they increase cheese yield and enhance milk flavor. DHI laboratories test for total proteins with electronic, high-speed, automated equipment.

Milk Solids-Not-Fat (SNF)
The solids portion of the milk minus the fat component represents about 8.5 to 9.2 percent of the total milk solids. SNF is of interest because of renewed use of component pricing for milk. (Also called PLM for protein, lactose and minerals.)

Modified Contemporary Comparison (MCC)
A calculation procedure adopted by USDA in 1974 to provide accurate sire summaries and cow indexes.



N                                                             Return To Index

National Association of Animal Breeders (NAAB)
The national organization made up of representatives from the artificial insemination (AI) industry. NAAB, which is administered by an executive vice president and elected officers, is headquartered in Columbia, Missouri.

National Cooperative Dairy Herd Improvement Programs (NCDHIP)
The national, industry-wide cooperative framework within which all DHI-related activities function.

NCDHIP Policy Board
The 12-member governing body for NCDHIP.

The national DHI organization, made up of member state DHI organizations and administered by an executive secretary and an elected board of directors. The office is located in Columbus, Ohio.



O                                                             Return To Index

Owner-sampler (OS)
DRPC Code 40. This type of testing plan allows dairy farmers to weigh and sample milk from their cows. Records are intended for management use only and are not official.

The status given to DHI records that follow the Official DHI Rules. Data collection is supervised and the dairy herd is subject to verification tests. Official records may be published for advertising and promotional purposes.

Official DHI
Used synonymously with DHI (see DHI).

Official DHI Rules
Basic and minimum standards to be followed uniformly and enforced in Official DHI and Official DHIR herds throughout the United States, ensuring accuracy and  uniformity .

A naturally secreted hormone that is important in milk letdown and the contraction of smooth uterine muscles during parturition.



P                                                             Return To Index

The process of giving birth.

Permanent Identification
Identification that stays with the animal for its lifetime and cannot be lost. Examples are tattoo, color markings and hot or freeze brand. (Also see Unique Identification.)

Potassium Dichromate
A milk preservative in tablet or granular form. A DHI milk sample contains 41 milligrams or less of potassium dichromate. (See Milk Preservative.)

Predicted Difference (PD).
Estimate of the genetic transmitting ability of dairy bulls for performance traits in the United States. PD is defined as the amount by which daughters of a bull will, on the average, differ in performance from the average breed performance in the genetic base period.

Predicted Difference Dollars (PD$).
A selection index value that combines the predicted differences for milk and components weighted by their gross economic value.

Preliminary Milk
The first milking of a three-milking verification test for herds milked twice daily. The purpose of the preliminary milking is to ensure complete milk out and to establish a 24-hour milking interval.

Premature Calving
Termination of pregnancy during the last trimester.

Preservatives  (See Milk Preservatives.)

Production and Type Index (PTI)
Combines PD$ and PD Type (PDT) on a 3 to 1 ratio thus ranking sires on their ability to transmit a balance of these traits. The index is used on Ayrshire, Brown Swiss, Guernsey and Jersey breeds.

Production Report
The computer report of production and management data which is returned to the dairy producer 5 to 7 days following the test day and after component sampling is completed at the laboratory. The records are processed at one of the DRPC's.

Progeny Test
An evaluation of the transmitting ability of an individual based on the performance of offspring.

Projected 305-Day Lactation
A method of predicting a cow's total yield in 305 days based on the information from a lactation in progress.

Protein  (See Milk Protein.)

An animal with two registered parents of the same breed.

Purebred Dairy Cattle Association (PDCA)
An organization made up of members of the six purebred dairy cattle registry associations: Ayrshire, Brown Swiss, Guernsey, Holstein, Jersey and Milking Shorthorn. PDCA is administered by an executive secretary and elected officers and is a cooperating member of NCDHIP.



Q                                                             Return To Index

Quality Certification Standards (QCS)
A set of national standards that must be met and maintained by state DHI organizations to assure the accuracy, uniformity and integrity of NCDHIP.



R                                                             Return To Index

Record (2x 305-day, ME)
Estimates how much the cow would have produced during the present lactation when milked twice daily in the first 305 days of her lactation if she had been a mature cow calving in an average month.

Procedure used by DHI supervisor or dairy producer to record milk and test-day data on a record sheet or barnsheet. Record in Progress (RIP). A cow's production from her calving date until the most recent test day.

Record Plan
Specific DHI program that provides a particular service to dairy farmers. The plans are either official or unofficial according to rules of the program.

An animal that is recorded in the Breed Registry Herdbook.

Registration Certificate
Proof that the parentage of an animal is known and is recorded in the Breed Registry Herdbook.

The degree of confidence or reliability the predicted difference (PD) or cow index (CI) for milk, fat, fat percentage, protein or physical type score.

Representative Sample
A sample of milk obtain thoroughly mixing or agitating the total quantity of milk produced by a cow. Milk meters are designed to collect automatically a representative sample from the total quantity of milk.

Herd owners who question the results of a regular test may request a retest of the herd not later than 15 days following the original test day. Expenses most retests are paid by the herd owner.

Rolling Herd Average (RHA)
Actual average milk and component production per cow for all cows in the herd for the immediate past 365 days. RHA's are updated with each new test.

A feed that is high in fiber content and relatively low in rate of digestion. (Also see Forage.)

Rule Violation
Dairy producers, their employees or DHIA supervisors who, for any reason, fail to follow the Official DHI/DHIR Rules or fail to report infractions of the rules, may be found in violation of those rules and be disciplined or dismissed according to the decision of the local or state DHI board of directors.



S                                                             Return To Index

Mechanical device to record milk weights to the nearest one-tenth of a pound. Scales usually are limited to 80 pounds per weighing and must have the ability to compensate for pail weight.

Selection Intensity
The margin of true genetic superiority of those animals selected in comparison to all those from which the choices were made.

Service Sire
The sire to which a female currently is bred. Service sire information should be reported on DHI barnsheets.

The male parent.

Sire Selection
Process of identifying bulls to be used as service sires with the goal of increasing the genetic potential of the herd.

Sketch (Photo)
A method of permanent identification to be cross-referenced with visible identification. Accurate sketches or photographs of Holsteins, Ayrshires and Guernseys provide unique identification.

A precise set of instructions, written in computer language, that is needed to make computers function.

Solids-Not-Fat  (See Milk Solids-Not-Fat.)

Somatic Cell Count
A measurement of the number of somatic cells present in a sample of milk. A high concentration of more than 500,000 somatic cells per milliliter of milk indicates an abnormal condition in the udder. (Electronic somatic cell counters are available in nearly all DHI laboratories to provide dairy farmers with an inexpensive screening test for subclinical mastitis.)

Somatic Cells
The cell content of milk is composed of approximately 75 percent leukocytes (white blood cells) from the blood and 25 percent epithelial cells from the secretory tissue of the udder. Leukocytes are present in response to infection or injury, and epithelial cells are present as a result of infection or injury. Collectively, these cells are called somatic cells.

A protein hormone produced by the pituitary gland, which stimulates growth of muscle, bone and mammary development in young animals and increases milk production in lactating animals by making available nutrients for milk synthesis and secretion.

Stage of Lactation
Period of milk production during a lactation determined by the length of time since parturition.



T                                                             Return To Index

A method of permanent identification to be cross-referenced with visible identification. Permanent ink used with tattoo numbers creates a lifetime record of identification in the ears of dairy cattle. Tattoos are used primarily in the Jersey and Brown Swiss breeds.

The process of collecting milk samples and recording milk weights. Sometimes called "test day".

Test Interval
The interval, in days, between successive DHI tests. As a routine procedure, a test interval shall not consist of less than 15, or more than 45 days. For Official DHI/DHIR records, the test interval shall not exceed 75 days.

Time Recording Device/Monitor
A mechanical/electronic device that automatically monitors the interval between milkings. The time is expressed in hours plus minutes, and the device must display the starting and ending time of the previous milking.

Times Milked
Cows are normally milked twice per day with records being labeled 2x; however, cows may be milked more frequently (3x, 4x, etc.).

Total Performance Index (TPI)
Method of ranking Holstein sires based on an index combining PD milk, PD percentage and PD type.

Process when ownership of a registered animal is changed and recorded in the Breed Registry Office or when ownership of a Verified Identification Program animal changes. When the ownership of the animal changes, the production credits must be transferred. This procedure is done by the DRPC with the assistance of the dairy producer and the DHI supervisor.



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Unified Series Eartag
A form of unique identification engraved in a metal tag and fixed to the ear of a dairy cow. Each number is unique with the first two numbers representing the state code, followed by three letters and four numbers.

Unique Identification
A series of nonduplicating numbers such as a registration, uniform series eartag or VPP number. These numbers are cross-referenced with permanent identification for registered, VIP and other recorded nonregistered animals. (Also see Visible Identification.)

U.S. Department of Agriculture (USDA)
The branch of the Federal government that is administered by the Secretary of Agriculture appointed by the President of the United States.



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Verification Test
A special test conducted on Official DHI/DHIR herds to verify production records of cows and herds or for investigation of rule violations. A supervised preliminary milking prior to the verification test is required to determine a 24-hour milking interval. (Tests may be ordered by breed organizations, state DHI boards of directors, state DHI managers and/or the Extension dairy specialist for NCDHIP.)

Verified Identification Program (VIP)
A program sponsored by the National DHIA, Inc., in which a DHIA supervisor verifies the required identification information for an animal. NDHIA issues an identification certificate, permanently identifying the animal and its parentage.

Visible Identification
A readily visible, numbering system attached to the animal that is used to identify the animal easily on test day.



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Procedure used by supervisors and dairy producers to determine the amount of milk given by a cow on test day.